1. Field of the Invention
This invention relates to a new class of novel inorganic-organic hybrid polymers that are formed from linear inorganic-organic hybrid polymers of varying molecular weight. These new high temperature oxidatively stable thermosetting polymers are formed from linear polymeric materials having repeat units that contain at least one alkynyl group for cross-linking purposes and at least one bis(silyl or siloxanyl)carboranyl group. These novel thermosetting polymers ca be further converted into ceramics at elevated temperatures.
2. Description of the Related Art
The cross linking of acetylenic polymers has been demonstrated by Neenan et al. in Hypercross-Linked Organic Solids: Preparation from Poly(aromatic diacetylenes) and Preliminary Measurements of Their Young's Modulus, Hardness, and Thermal Stability published in 21 MACROMOLECULES 3525-28 (1998), incorporated herein by reference. The reaction for cross linking acetylenic polymers illustrated by Neenan et al. is as follows: ##STR1## where n is a positive integer. Other similar cross linking reactions are demonstrated by Callstrom et al. in Poly[ethynlyene(3-n-butyl-2,5-thiophenediyl)-ethynylene]: A Soluble Polymer Containing Diacetylene Units and Its Conversion to a Highly Cross-Linked Organic Solid published in 21 MACROMOLOCULES 3528-30 (1988), incorporated herein by reference. For example, see the reactions shown below taken from Callstrom et al.: ##STR2##
There is a need for oxidatively stable materials that have thermosetting properties for making rigid components therefrom, such as engine parts, turbine blades and matrices. These components must withstand high temperatures and be oxidatively stable and have sufficient strength to withstand the stress put on such components. Thus, there is a need for carborane-silane or carborane-siloxane cross-linked thermosetting polymeric materials that show high temperature stability where weight percentage loss is limited to 20% or less when heated in excess of 600.degree. C. in an oxidative environment. In addition, there is a need for carborane-silane or carborane-siloxane cross-linked thermosetting polymeric materials that behave more as rigid materials and less as elastomeric materials.